> hello dieter,
> so, that means that if i connect a voltage in the
> range of +12 to -12 volts, the a155 switching function
> will just not work or there is danger of damaging the
> a155
> best regards,
> Bakis.

There is some chance that a voltage more negative than -5V will destroy the
multiplexer circuit of the A-155 (but normally it will clip only). Within
the A-100 a negative voltage in this range can be generated only in a very
complicated way, e.g. by inverting a positive voltage beyond +5V. Since the
A-155 is available (i.e. nearly 10 years) we never had a fault caused by a
negative voltage at the external inputs.

Best wishes
Dieter Doepfer